This invention relates to an automated apparatus for loading and unloading motor vehicles.
The apparatus of Italian patent 1,228,235, to which reference should be made as the state of the art, was constructed for use in rapidly and flexibly loading and/or unloading motor vehicles in which the load is arranged either on pallets or the like or individually.
This Italian patent relates to an apparatus for automatically loading and unloading motor vehicles, where the term "motor vehicle" means either a truck with full trailer or a tractor with semitrailer, to be loaded through a rear door.
In using the apparatus of that Italian patent various problems were encountered, to the extent that it was not possible to achieve maximum reliability and versatility.
In this respect, the lifting and/or gripping means associated with the manipulator-conveyor unit were unable to ensure straight-line movement of the unit either along the loading/unloading platform in the loading station or within the vehicle body.
A reason for this non-uniform and not always correct movement is that the pallets or other load supports to be handled are not of sufficient size to totally contain the loaded products within their base perimeter. This is further emphasized if the products are not correctly positioned with the result that they extend beyond the base perimeter. Such variations make it almost impossible to insert the thus-loaded pallets into the vehicle.
A further contributing factor is that the vehicle does not always have perfectly vertical walls because of the difference in type diameters, different suspension heights etc. The pallet being inserted tends to jam at its guide rollers, which are provided to the side of the manipulator-conveyor unit to facilitate the movement of the pallets and their insertion into the vehicle. It has also been observed that such an apparatus is unable to solve the problems connected with possible differences in the relative loading arrangement of rectangular pallets.
In this respect, because of the standard width of a vehicle load floor and in order to optimize and stabilize its weight distribution, the pallets have to be arranged variably and/or alternately in making up the transverse rows. As the pallets are rectangular, with their two side dimensions (for example 800 mm and 1200 mm) being different sub-multiples of the same possible loading width (2400 mm) between the inner walls of the vehicle, the pallets have necessarily to be arranged by being rotated through 90.degree. one to the other in the two cases.